Electric Motorcycle¶
Part of the motivation for doing fabacademy was derived from my long term project to convert my motorcycle into an elevtric one. For that I need to understand how the components for such a product work and how they are linked together. Eventually I will probably buy standard components, but to make the right choice I should understand at least the basics.
In the light of the question during week 18: how to disseminate my final project including how future possibilities look like, for the noise drum, there is no plan. The noise drum is just some fun with a first spiral of learning into the main goal, the electronic motorbike.
Research¶
For research I have followed the MOOC Electric Cars from DelftX on the edX platform. It gives some basic knowledge about the main parts of electric vehicles (EVs). From there I started to conceptualise what I need for me E-bake conversion.
Basically the whole fabacademy journey was also part of my research path. I learned some basic electronics and programming skills and boosted my digital fabrication knowledge to a higher level.
Components¶
To retrofit an electric system ionto my motorcycle I need the following components, though “systems” is probably more at place here.
- Electric Motor It will need around 60 kW power and a torque of 200 Nm. Most common and for me the best choice is a permanent magnet motor that operate frequency controlled.
- Inverter The batery is DC, so you need an inverter to turn that into 3 phase AC. But this inverter also needs to operate as a rectifier when you are in the mode of regenerative breaking.
- Frequency Control To control the speed you need a controller that can regulate frequency and current for the motor. To maximise the available energie it should be able to work both ways: to drive and to break in which case the motor will operate as a generator.
- DC/DC Converter Electric motors in EVs usually operate on a higher voltage that the battery, so you have to step up the voltage to the required level or step down in case of regenerative breaking.
- Battery E-bikes of course also need batteries. The most used type is Lithium-ion batteries, but there are different versions available. This is nothing you will make yourself, but it’s a matter of choosing the right model and design the assembly in such way that it will fit into the space where currently the combustion angine is.
- Rectifier To charge from the AC-net at home or at public charging spots you need a rectifier to convert that into the right DC voltage of the battery.
- BMS For safety and to get the maximum life time of the batteries you need a batery monitoring system. It measures voltage, current and temperature of each individual cell to balance the (dis)charge and to detect malfunctioning ones. Usually the BMS also regulates the rectifier during charging and it also communicated with the DC fast charging stations.
- Construction In the BMW the engine block also functions as a frame part. So if I demount the engine and the gearbox, I will have to design a new frame to carry all the new parts and to connect the rear frame to the front and to the steering construction.
Motor Control¶
During my fabacademy period I have tried to make my own VFD (variable frequency drive). The noise drum project was just a simple and fun way to create something that could make use of a 3 phase motor and VFD. You can have a look on the noise drum page to discover how that went.
Spoiler alert: it failed. :-/ I learned a lot about mosfets and gate drivers, but unfortunately not enough to succeed. Details of such a device are too specific, so within the fablab community nobody was able to help me out here.
After finishing fabacademy I will go on with my research and build my VFD.